<style>
    .container {
        display: flex;
        /* justify-content: flex-start; */
        /* 
            flex-start center flex-end space-between space-around
        */
    }

    p:first-child {
        background: red;
    }

    p:nth-child(2) {
        background: yellow;
    }
    p:nth-child(3) {
        background: rgb(0, 255, 76);
    }
    p:nth-last-child(1) {
        background: blue;
    }

    p {
        width: 200px;
        height: 200px;
    }
</style>

<div class='container'>
    <p>1</p>
    <p>2</p>
    <p>3</p>
    <p>4</p>
</div>